This invention relates to the drying or curing of agricultural or other organic products prior to use or storage and, more particularly, to apparatus for drying or curing such products in a relatively short period of time.
Tobacco must be cured before it can be used for smoking products. This is normally accomplished by allowing it to hand in curing sheds over long periods of time. Such sheds use a great deal of space and require periodic maintenance. Further, a great amount of manual effort is required to place the tobacco in the shed and to remove it once it has been cured.
Grains such as soybeans, peanuts, corn, sugarcane, etc. must be dried before they can be stored in silos. Typically 10-15% of their moisture content must be removed. In order to accomplish this drying, open-topped trailers in which the grain is gathered are positioned adjacent to an oil or gas fired heater. A conduit is connected from the heater to the bottom of the trailer and hot air from the heater is forced upward through the grain by a fan. Farmers must pay for this drying process or must sell their moist grain at a lower price. Drying of grain by forced hot air (i) is time consuming, requiring two to five days, (ii) is energy inefficient, since the air exiting from the trailer is still at a very high temperature, and (iii) requires the movement of large numbers of trailers from the field to the heater and then to the storage facility.
Microwave technology has for sometime been utilized to cook food. However, in this application it must be assured that the microwaves are confined to the oven in which the cooking is performed so that they do not harm the user. To this end microwave ovens are provided with a great deal of insulation and special doors that reduce leakage. As a result, the use of microwaves for in-line operations involving the transport of items on a conveyor belt into a microwave field is not indicated in the prior art.